Multicomponent Reactions (MCRs) are one-pot reactions, in which three or more starting materials react to form a product, where basically all or most of the atoms contribute to the newly formed product. Speed, diversity, efficiency, atom-economy and environmental friendliness are some of the notable features of this class of reactions. The most important MCRs are the isocyanide-based reactions such as the Passerini three-component reaction and the Ugi four-component reaction. Moreover, a variety of heterocycles can be constructed using the MCR strategy, where zwitterionic intermediates are generated by the addition of nucleophile to activated C—C multiple bonds followed by their interception with a third component.
Arynes are highly electrophilic reactive intermediates, which have been extensively utilized in various carbon-carbon and carbon-heteroatom bond-forming reactions. One of the important aspects of aryne chemistry is multicomponent reaction, which mainly include the initial addition of nucleophiles to arynes and subsequent trapping of the aryl anion intermediate with electrophiles. If the nucleophile and electrophile do not belong to the same molecule, the overall process is a unique three-component coupling, where the aryne is inserted between the other two coupling partners (cqn (1)). This versatile transition-metal-free methodology has been applied to the synthesis of valuable heterocycles and in natural product synthesis. Ortho alkynyl anilines are the important precursor for the synthesis of substituted indoles, 3,4-hydroquinolinones & other heterocycles which are useful scaffold for synthesis of various drugs molecules and natural products.
Article titled, “Multicomponent Multicatalyst Reactions (MCR): One-Pot Synthesis of 3,4-Dihydroquinolinones” by Lei Zhang et al. published in Org. Lett., 2013, 15 (9), pp 2128-2131 relates to a Rh/Pd/Cu catalyst system for synthesis of dihydroquinolinones in one-pot, two operations. The reaction features the first triple metal-catalyzed transformations in one reaction vessel, without any intermediate workup.
Article titled, “Synthesis of 3-Sulfenyl- and 3-Selenylindoles by the Pd/Cu-Catalyzed Coupling of N,N-Dialkyl-2-iodoanilines and Terminal Alkynes, Followed by n-Bu4NI-Induced Electrophilic Cyclization” by Yu Chen et al. published in J. Org. Chem., 2009, 74 (17), pp 6802-6811 reports 3-Sulfenyl- and 3-selenylindoles that are readily synthesized by a two-step process involving the Pd/Cu-catalyzed crossing coupling of N,N-dialkyl-ortho-iodoanilines and terminal alkynes and subsequent electrophilic cyclization of the resulting N,N-dialkyl-ortho-(1-alkynyl)anilines with aryl sulfenyl chlorides or aryl selenyl chlorides. A variety of 3-sulfenyl- and 3-selenylindole derivatives bearing alkyl, vinylic, aryl, and heteroaryl substituents are prepared. The article further discloses preparation of 3-sulfonyl- and 3-sulfinylindoles by facile oxidation of the corresponding 3-sulfenylindoles.

Article titled, “An Efficient, Microwave-Assisted, One-Pot Synthesis of Indoles under Sonogashira Conditions” by Chen Y et al. published in Tetrahedron, 2009; 65 (44); pp 8908-8915 reports an microwave-assisted, one-pot, three-component coupling reaction for the synthesis of indoles. The reaction is carried out in two steps under standard Sonogashira coupling conditions from an N-substituted/N,N-disubstituted 2-iodoaniline and a terminal alkyne, followed by the addition of acetonitrile and an aryl iodide.

Article titled “Copper-catalyzed arylation of alkenyl aziridines via three-component coupling reaction involving alkynes and benzyne” by F Berti et al. published in Synlett, 2012; 23(17); pp 2463 reports alkenyl aziridines which can be successfully arylated in a three-component coupling triggered by in situ generated benzyne with a simple copper catalyst (CuI-PPh3), without the need of any palladium salts. A new domino reaction with ethyl propionate to give tetrahydrophenanthridine is also described.
The processes described in the art involves activated systems which are air and moisture sensitive, are multiple step processes and involve use of expensive catalyst thereby making the process costly and industrially not feasible. In view of the above, there remains a need in the art to provide a process for synthesis of ortho alkynyl anilines that ameliorates the drawback of the known processes, which remains the objective of the invention.